Pneumatic drill.



No. 856,651. PATENTED JUNE 11, 1907. P. H. MURPHY.

PNEUMATIC DRILL.

APPLICATION IILED.DEO. 11 1905- Q 3 SHHBTS-SHEET 1- a as J6 67 4 finesse-s: W InveizZi':

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No. 856,651. PATENTED JUNE 11, 1907.

. P. H. MURPHY.

PNEUMATIC DRILL.

APPLICATION FILED DEC. 11, 1905.

3 SHEETS-SHEET 2.

PATENTED JUNE 11 1907.

P. H. MURPHY. PNEUMATIG DRILL. APPLIOATION FILED DEO.11, 1905.

3 SHEETS-SHEET 3.

' part of this specification and wherein like UNITED STATES PETER I-I. MURPHY, OF ST. LOUIS, MISSOURI.

PNEUMATIC DRILL.

Specification of Letters Patent.

Patented June 11, 1907.

Application filed December 11,1905. Serial No. 291,248.

Be it known that I, PETER H. MUnrnY, a citizen of the United States, and a resident of the city of St. Louis and State of Missouri, have invented a new and useful Improve ment in Pneumatic Drills, of which the fol* lowing is a specification.

My invention relates to pneumatic drills and has for its principal objects to produce a pneumatic drill capable of being converted into a boring machine; to produce a drill cas- 1 ing having the top or bottom and four walls in a single integral piece and closed by a plate; to provide a strong casing in which the parts of the drill may be readily assembled or disassembled; to provide a double acting motor or engine of sim le construction; to produce a reversible c rill; and other objects hereinafter more fully appearing.

My invention consists in the arts and in the arrangements and combinations of parts hereinafter described and claimed.

In the accompanying drawings forming a symbols refer to like parts wherever they occur, Figure 1 is a plan view of the drill, z broken away at one side and showing one of i, the engines in section; Fig. l is a vertical sectional View on the line 22 of Fig. 1 Fig. 3 is a central vertical sectional view, the engines and connected parts being omitted; Fig. 4 is a horizontal sectional view through the casing; Fig. 5 is a vertical sectional view on the line 55 of Fig. 4:, Fig. 6 is a fragmentary elevational view of one wall of the drill showing the throttle-valve seat; Figs. 7, S and 9 are views of the throttlevalve; Fig. is a fragmentary sectional view through the main spindle as arranged to receive a boring-bar.

The frame and housing of the present drill are combined in a casing 1 which serves the purpose of both. The top, the four walls and a portion of the bottom of the casing are made in a single, integral casting. At the center of the top is a tubular boss 2 extending inwardly and a short tubular boss 3 extending outwardly. These alined bosses furnish the principal bearing for the main spindle of the drill. The top and bottom are also provided with integral tubular bosses 4, 5 which serve to support the main valves of the engines and the engine cranks, respectively. The air ducts are also produced in the casting being produced by cores. The courses of the air ducts will be described in connection with 3 the description of the engines.

1 riphery of the spindle at its end.

The casing is closed on the lower side by a circular ca plate 6 which is provided with screw-threa s on its periphery and screws into the bottom of the casing.

Inside of the tubular boss 2, a bushing 7 is arranged which has a flange 8 overlapping the lower end of the boss. The bushing is approximately two-thirds the length of the boss, the main spindle 9 is cylindrical, extends somewhat abm'e the upper end of the bushing 7 and has a shoulder bearing on the lower end of the bushing. The spindle gear 10 is rigidly secured on the main spindle A bearing ring 11 is secured to the upper end of the main spindle. It slips over the end of the spindle and has an inwardly extending annular flange bearing on the same. The bearing ring is held against rotatory movement relative to the spindle by a pin 12 which engages a notch or groove in the pe- On its upper face, the bearing ring is provided with a runway for balls. The boss 3 of the casing is externally screw-threaded and a spindle nut 13 fits on the same. A set screw 14 mounted in the bearing nut may be screwed down into contact with the face of the boss 3 and thus secure the nut against change of adjustment by vibration or shock. A bearing ring 15 having a ball race in its lower face fits inside of said spindle nut and is connected to the same by dowel-pins 16. Balls are arranged between the bearing rings 11 and 15 and thus a ball thrust bearing is provided for the spindle. The spindle nut 13 is provided with an outwardly extending sleeve 17 which is provided with a screw-thread on its interior. A hollow feed screw 18 fits inside of the sleeve of the spindle nut. At its upper end it is provided with internal screw-threads. An inner feed screw 19 fits inside of the outer feed screw and is provided at its upper end with the usual conical bearing-point 20 of hardened steel. By this arrangement all the thrust on the main-spindle is thrown upon the spindle nut and feed-screws and none of it is thrown upon, or transmitted through the casing 1.

The main spindle has a bearing for its lower end in the cap plate 6. A central hole in said cap-plate is provided with a flanged- ICC bushing 21 in which the main spindle bears.

An internal feather or key 22 is secured in the mam spindle. It may be simply a straight key or may have its ends bent at right angles flanges of the heads.

and inserted in notches in the ends of the main spindle. In any event, the key is permanently riveted in place. A spindle socket or tool holder 23 fits in the main spindle 9. It has a shoulder bearing on the end of the main spindle whereby thrust upon the spindle socket and the tool held therein is transmitted to the main spindle. The spindle socket is held in place by means of a split ring 24 which lies in registering grooves in the socket and the main spindle. The split ring tends to contract, but may be forcibly expanded. The groove upon the exterior of the spindle socket has radial depth which is approximately half the diameter of the wire forming the split ring. The groove in the spindle is deeper to permit the expansion of the ring when the socket is being inserted or removed. To insert the socket sufficient force is exerted upon it to expand the ring; to remove the socket the force may be exerted by the feed screw which may be screwed in far enough to bear on it as shownin Fig. 3. Immediately outside of its bearing in the cap-plate the main spindle is externally screw-threaded. An internally screw-thre aded guard ring 25 fits on the spindle and covers the end of the bearing. Thus, the en trance of dust and borings is prevented.

The arrangement of the main spindle and parts cooperating therewith, which has just been described, permits the conversion of the drill into a boring machine. The spindlesocket 23 may be removed. The spindle nut 13 may be unscrewed and removed with the feed-screws. The bearing rings 11, 15 and balls may then be lifted out. And then the main spindle is open from end to end, as shown in Fig. 10. A boring bar may now be .passed through the main spindle and driven by the same.

The engines which drive the main spindle are of the oscillating type. There are two engines the construction of which is the same. At one end is a cylinder head 26 which has a centrally arranged tubular ex tension 27 and peripheral internally-threaded flange 28. The tubular extension 27 serves to receive the packing gland and nut for the piston rod. Concentric with the peripheral flange 28 there is a circular groove in the in ner face of the cylinder head. At the opposite end the engine has a valve cylinder head 29. Like the first mentioned cylinder head, it has a peripheral internally-threaded sleeve 30 and a concentric circular groove. The wall of the cylinder is double and consists of two concentric sleeves or cylinders 31, 32. The outer cylinder 31 is screw-threaded at its opposite ends and fits in the peripheral The inner cylinder 32 fits snugly in the circular grooves of the heads. The heads are screwed down on the outer cylinder until the inner cylinder is firmly seated at the bottoms of the grooves in the heads. The inner cylinder has a number of perforations 33 at the end opposite the valve cylinder head. The valve cylinder head has a port 34 opening into the space between the two cylinders or sleeves. The valve cylinder head also has a port 35 opening into the inner cylinder or sleeve.

The main valve of the engine is a cylindrical block 36. In it are bored two longitudinal holes or ducts 37, 38 which are closed at their open ends by plugs 39, 40, respectively. From each duct two ports extend to the periphery of the valve. These ports, in the case illustrated, consist of a plurality of bored holes. .This construction is cheap and convenient. It is obvious, however, that slots having the same area as. the holes could be used. The ports 41, 42 of the duct 37 lie inside of the ports 43, 44 of the duct 38.

The valve cylinder head has a cylindrical bearing portion 45 into which its ports 34, 35 open. A bushing 46 is fitted tightly in this bearing and has slots or ports 47, 48 communicating with the ports 34 and 35, respectively, and become in effect a continuation of the same. This construction is one easily and cheaply manufactured. The ports 34 and 35 can be cored out in casting the cylinder head. The slots or ports 47, 48 are cut in the bushing before it is inserted and, hence, it is a simple operation. And when the parts are assembled, the slots 47, 48 form the portions of the ports 34, 35 which it is required to have well finished and accurately located.

The main valve 36 extends through the bushing 46 in the bearing portion 45 of the valve cylinder head. It is seated in the bosses 4 of the case 1. A pin 49 secured in the main valve enters a slot in one of the bushings and thus the proper location of the valve is secured. The bushing through which the valve is inserted is closed by a screw-plug 50. The ports 47 48 in the valve cylinder head are so located that when one is in communication with a port leading from one of the ducts of the valve (for example the port 43 of the duct 38) the other will be in communication with the port leading from the other duct of the main valve (for example, the port 42 of the duct 37).

The piston 51 of each engine is of the usual type and its rod 52 is directly connected to a crank 53. The crank carries a pinion 54 which meshes with the spindle gear 10 and transmits the power of the engine to said gear. The crank is j ournaled at one end in the boss 5 on the casing which is provided with a bushing 55 and is closed by a dust plate 56 perforated at the center by a small hole through which oil may be introduced. At its opposite end the crank is journaled in a bearing plug 57 which is screwed in a hole which is principally in the casing but is partly in the cap-plate 6, the hole being IIS tapped after the cap-plate is assembled in the casing. The bearing plug is provided with an anti-friction bushing 58.

There are two engines such as that described above. Their cranks are at diagonally opposite corners of the casing and the crank pinions bear upon the spindle gear at diametrically opposite points. Consequently, the forces acting on the spindle gear are balanced. The cranks are set at right angles to each other and, hence, both cannot be on the dead center at one time. The main valves for the engines are arranged at the other diagonally opposite corners.

he air ducts in the casing, mentioned in describing the casing, communicate with the main valves. In a throttle-valve lug near the middle of one wall of the casing two ducts 59, 60 start. The duct 59 extends to the angle of the casing and follows it around, as indicated in Fig. 4, past one of the main valves and to the other main. valve. A branch duct 59'" extends downwardly and laterally into communication with the duct 37 of the main valve passed by the duct 59. At its end the duct 59 communicates with the duct 38 of the other main valve. The air duct 60 branches as soon as it reaches the angle of the case, one branch communicating with a duct 38 of one main valve and the other branch communicating with the duct 37 of the other main valve.

The throttle-valve lug has a smoothly finished outer plane surface into which both ducts open at diametrically opposite points. At one side and between the two ports thus formed, is a port of an exhaust duct 61 finding its outlet at the side of the lug. This exhaust port is elongated for a purpose that Will presently appear. At its center the lug has a bearing 62. The lug is externally screw-threaded and upon it fits a throttle valve housing 63. Within this housing is arranged a throttle valve 64 provided with a centrally located pin 65 arranged to fit in the bearing 62 in the lug. The throttlevalve is provided with two ducts 66, 67 passing entirely through it and an elongated duct 68 which is merely recessed. A sleeve 69 fits inside of the housing and extends longitudinally beyond it. It carries a pin or pins 70 which engage a hole or holes 71 in the upper face of the valve. A hose coupling 72 screws on the end of the slee 'e 69 and serves as a handle by means of which l the sleeve and throttle valve may be turned. To properly locate the valve in any desired adjustment the following means are used: In the valve housing an externally screwthreaded sleeve 73 'is mounted. Inside of said sleeve is a spring 74 which presses a ball 75 inwardly in contact with the face of the throttle valve. On the face of the throttle valve is an indentation 76 which the ball will drop into and thereby yieldingly hold the throttle valve'in its middle or ineffective position. On opposite sides of said indcntationare stop pins 77, 73 which will strike the ball and stop the throttle valve in its extreme positions.

The air admitted through the hose coupling 72, into the sleeve 69, holds the valve closely to its seat and may be directed by the same into either of the ducts 59 or 60. hen in one extreme position the duct 66 is in communication with the air duct 60 while the duct 68 connects the air duct 59 and the exhaust duct 61. When in the other extreme position, the duct 67 is in communication with the airduct 59 and the duct 68 connects the duct 60 and the exhaust duct 61. Thus, by manipulation of the throttle valve the direction of rotation of the tool may be reversed. Consider the parts in the position shown in Fig. If the valve is so set that live air is admitted to the duct 59, then the duct 37 of the main valve will be a live air duct and the duct 38 will be an exhaust duct. Thus, live air will pass through the ports 42 and 34 into the annular chamber between the cylinders 31, 32 and through the ports 33. The piston will be forced to the right and right-handed rotation of the crank pinion 54. will be caused. On the other hand, if the valve were so set that live air were admitted to the duct 60, then the duct 37 of the main valve will be an exhaust duct and the duct 38 will be a live air duct. Under these circumstances live air would pass through the ducts 43 and 35 into the cylinder and force the piston to the left, causing left-handed rotation of the crank pinion 54.

Obviously, the drill is capable of considerable modification within the scope of my invention and therefore I do not wish to be limited to the specific construction shown and described.

What I claim as my invention and desire to secure by Letters Patent is:

1. A pneumatic drill comprising an inte gral hollow casii'lg provided with an inwardly extending tubular boss integral therewith, said tubular boss having a bushing therein constituting a main spindle bearing, a main spindle journaled in said bearing, a gear wheel rigidly secured to said spindle, said casing having an opening in one side to admit said gear wheel, a cap-plat to close said opening and provided with an opening having a bushing therein constituting a bearing for one end of said spindle, and means to actuate said spindle operatively connected to said .gear wheel.

2. A pneumatic drill comprising an integral hollow casing provided with an inwardly extending tubular boss integral therewith, said tubular boss having a bushing therein constituting a main spindle bearing, a main spindle journaled in said bearing, a gear wheel rigidly secured to said spindle, said casing having an internally screw-threaded opening in one side to admit said gear wheel, a cap plate to close said opening having screw threads on its periphery and provided with an opening having a bushing therein constituting a bearing for one end of said spindle, and means to actuate said spindle operatively connected to said gear wheel.

3. A pneumatic drill comprising an integral hollow casing having an opening in one side to admit the working parts and a capplate to close said opening, a main spindle journaled in said casing, a gear wheel secured to said spindle, an engine mounted in said casing and having a crank shaft operatively connected. to said gear wheel, said crankshaft being journaled at one end in a bearing in said casing and at its opposite end in a removable bearing plug, the hole to receive said bearing plug being partly in said casing and partly in said cap-plate, whereby said capplate is held against rotation when said bearing plug is in place.

4. A pneumatic drill comprising a main spindle, a double acting engine operatively connected to said main spindle, and having a piston and a valve adapted to alternately admit pressure to each face of said piston, a reversing throttle valve, air ducts communicating at one end with said engine valve and communicating at their other ends with said throttle-valve, an exhaust duct communicating with said throttle-valve, said throttle-valve being arranged to connect either of said first-mentioned air duets with said exhaust duct and the other with a source of supply of compressed air.

5. A pneumatic drill comprising a casing having open-ended spindle bearings forming an opening through the casing from side to side, an open ended spindle journaled in said bearings, a spindle nut removably secured upon the outside of said casing, a thrust bearing arranged between said nut and one end of said main spindle, a tool holder removably mounted in the other end of said main spindle, a feed screw mounted in said spindle nut, and actuating means for said main spindle mounted in said casing.

6. A pneumatic drill comprising a casing having open-ended spindle bearings forming an opening through the casing from side to side, an open-ended spindle journaled in said bearings and provided with a permanently mounted internal key, a spindle nut removably secured upon the outside of said casing, a thrust-bearing arranged between said nut and one end of said main spindle, a tool holder removably mounted in the other end of said main spindle and having a key-way to receive said key, a feed screw mounted in said spindle nut, and actuating means for said main spindle mounted in said casing.

7. A pneumatic drill comprising a casing,

a main spindle mounted in said casing, means to actuate said spindle mounted in said casing, a thrust bearing ring removably connected to one end of said main spindle, a tool holder removably mounted in the other end of said spindle, a spindle nut secured to said casing and having a bearing ring arranged to i with said first mentioned bearing cooperate a feed screw mounted in said spinring, and dle nut.

8. A pneumatic drill comprising a casing, a main spindle and means to actuate said spindle mounted in said casing, a tool-holder arranged to enter said spindle, said tool-holder and said spindle having registering grooves in the surfaces in contact, and a split-ring of resilient material located in said grooves, the normal diameter of said ring being less than the diameter of said tool-holder at the bottom of its groove, whereby said ring tends to embrace said tool-holder closely.

9. In a pneumatic drill, an engine coml prising cylinder heads, concentric separated cylinders, means for connecting said heads to the ends of said cylinders, and forming an annular chamber between them, the inner of said cylinders forming a piston-chamber, and a iston fitting in said piston-chamber, one of said heads having ports opening, respectively, into one end of said piston-chamber and said annular chamber, and said inner cylinder being provided with ports leading from said annular chamber intothe opposite end of said piston-chamber.

10. In a pneumatic drill, an engine comprising cylinder heads h aving screw-threaded peripheral flanges and circular grooves concentric with said flanges, a cylinder screwed upon said flanges 'inder fitting at its opposite ends in said rooves and forming a piston-chamber, said cylinders forming an annular chamber be tween them, and a piston fitting in said piston chamber, one of said heads having ports opening, respectively, into one end of'said iston chamber and said annular chamber, and said inner cylinder being provided with ports leading from said annular chamber into the opposite end of said piston chamber.

11. In a pneumatic drill, an engine comprising cylinder heads, concentric separated cylinders, means for connecting said heads to the ends of said. cylinders and forming an annular chamber between them, the inner of said cylinders forming a piston chamber, one of said cylinder heads having a bearing portion provided with a valve seat and ducts leading from said valve seat to said pistonchamber and said annular chamber, respectively, a valve fitting in said valve seat and provided with parallel longitudinal air ducts and a pair of symmetrically located ports communicating with each of said ducts, said ports being so arranged that each of said ducts in said cylinder head will, respectively,

at its opposite ends, a cyl-- i into each of said alternately communicate with one port of" said pair of ports, and a piston reciprocating'ly mounted in said piston chamber.

12. In a pneumatic drill, an oscillating engine comprising a cylindrical main valve having two longitudinal air ducts and a pair of symmetrically located lateral ports opening duct-s, a piston cylinder having a bearing portion surrounding said valve and, provided with a rigidly mounted bushing having two ports, said ports being arranged to each communicate alternately with one portof each of said pairs of ports in said main valve, said cylinder being provided with air ducts leading, respectively, to the opposite ends of said cylinder and connnunicating With said ports in said bushing, respectively, and a piston in said piston chamber.

13. In a pneumatic drill, an oscillating engine comprising a cylindrical main valve ha ving two longitudinal air ducts and a pair of symmetrically located lateral ports opening into each of said ducts, a valve cylinder head I having a bearing portion surrounding said valve and provided with a rigidly-mounted bushing having two ports, said ports being arranged to each communicate alternately with one port of each of said pairs of ports in said main valve, a second cylinder head, concentric separated cylinders connecting said cylinder heads and forming an annular chamber between them, the inner of said cylinders constituting a piston-chamber, said valve cylinder head having air ducts opening, respectively, into said annular chamber and said piston-chamber and communicating with said ports in said bushing, respectively, and a piston in said piston chamber.

In witness whereof, I have signed my name to this s 'ieci'lication in the presence of two subscribing witnesses this 8th day of December, 1905.

PETER ll. MURPHY. i tnesses:

JAMES A. CARR, J. B. MaoowN. 

